This invention relates to a self-closing sliding door assembly.
The use of self-closing hydraulic door closer assemblies for pivotably mounted doors has been common practice in the industry for many years. Such hydraulic door closer assemblies generally include hydraulic closer means which are mounted on the frame of the doorway and an arm which is pivotably secured to the body of the closer means at one end and to the door at its other end. The hydraulic mechanisms provided in the closer body serve to rotate the arm and hence urge the door back to its original closed position after it has been opened.
While such hydraulic door closer mechanisms have proved to be very successful for closing swinging or pivotably mounted doors, the nature of their mode of operation has in the past made them unsuitable for use with sliding doors. Nevertheless, given the relatively low cost of such hydraulic door closing mechanisms, it is preferable that they be adapted to operate to close sliding doors without requiring a completely new type of closer assembly mechanism.
With this object in mind, Australian patent 673232 to the current applicant discloses a self-closing sliding door assembly which can operate using readily available hydraulic door closing mechanisms. However, it suffers from the disadvantage that the force exerted by the door closing mechanism on the sliding doors varies dramatically with the degree to which the door has been opened. This is because it operates via an arm which follows a track provided on a door. As the arm moves along the track, the angle the arm makes with respect to the door closer changes quite substantially and as a result the amount of force exerted by the door closer varies substantially with changing angle.
There is therefore a need for a self-closing sliding door assembly which operates on a principle requiring less change of angle than that required for the operation of the door closer assembly described in patent 673232.
The invention provides a self-closing sliding door assembly comprising,
a doorway in a wall,
a substantially planar door mounted for slidable movement with respect to the doorway to open and close the doorway,
closer means mounted on one of the door and wall having a drive shaft rotatable about an axis, and
an arm assembly having first and second arm members connected to each other by a first pivotal join, the first arm member being connected to the drive shaft and the second arm member being connected by a second pivotal join to the other of the one of the door and wall,
wherein the drive shaft is arranged to urge the first arm member to pivot about the axis whereby the arm assembly urges the door to close the doorway.
Suitably, the angle subtended between a first straight line drawn between the axis and the first pivotable join and a second straight line drawn between the first pivotable join and the second pivotable join is between 10xc2x0 and 50xc2x0 when the doorway is closed. More suitably the angle should be between 15xc2x0 and 35xc2x0.
The wall may comprise a frame for the doorway. The closer means may comprise a hydraulic door closer. The hydraulic door closer may be arranged to pivot the first arm in a plane parallel to the plane of the door. The closer means may be mounted on the doorway frame.
For aesthetic reasons, it is preferred that both of the arm members may be directed to extend generally parallel to the horizontal when the door is closed. The second arm member may comprise a first portion extending substantially horizontally from the first pivotable join and a second portion extending from the opposite end of the horizontal portion substantially vertically to the second pivotal connection with the door when the door is in a closed position.
When the door is opened to its maximum extent, it is preferred that the combined horizontal span of both the first and second arm members in this position be at least two thirds of the width of the doorway. Suitably the span should be equal to or greater than the door way to ensure that the doorway is completely unobstructed by the door.
Preferred aspects of the invention will be described with reference to the accompanying drawings.